219968

Appears in sequences

• Square chains: the number of permutations (reversals not counted as different) of the numbers 1 to n such that the sum of any two consecutive numbers is a square.at n=26A071983
• Arises from color-symmetrized counting of tensor invariants.at n=9A232217
• Triangle T(n,r) read by rows: order of the semigroup of orientation-preserving partial transformations of n elements with breath r.at n=41A289710